Data processing apparatus, color identification method, non-transitory computer readable medium, and color chart

ABSTRACT

A data processing apparatus includes an obtaining unit and a converting unit. The obtaining unit obtains measured color sample data, which represents values obtained by measuring color samples on a color chart with a color measuring device, and image data, which represents an image of the color chart and a target object captured with an image capturing apparatus. The converting unit converts captured target object color data, which represents a value of a color of the target object included in the image data, into estimated target object color data, which represents an estimated value of the color of the target object identified if the color of the target object were measured with the color measuring device, on the basis of the measured color sample data and captured color sample data, which represents values of the multiple color samples included in the image data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 fromJapanese Patent Application No. 2016-062586 filed Mar. 25, 2016.

BACKGROUND Technical Field

The present invention relates to a technique for identifying the colorof a target object.

SUMMARY

According to an aspect of the invention, there is provided a dataprocessing apparatus including an obtaining unit and a converting unit.The obtaining unit obtains measured color sample data and image data.The measured color sample data represents values obtained by measuringmultiple color samples on a color chart with a color measuring device.The image data represents an image of the color chart and a targetobject captured with an image capturing apparatus. The converting unitconverts captured target object color data into estimated target objectcolor data on the basis of the measured color sample data and capturedcolor sample data representing values of the multiple color samplesincluded in the image data. The captured target object color datarepresents a value of a color of the target object included in the imagedata. The estimated target object color data represents an estimatedvalue of the color of the target object identified if the color of thetarget object were measured with the color measuring device.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 illustrates apparatuses and the like used in a coloridentification method according to an exemplary embodiment;

FIG. 2 illustrates a color chart according to the exemplary embodiment;

FIG. 3 illustrates a configuration of a computer according to theexemplary embodiment;

FIG. 4 illustrates a configuration of a data processing apparatusaccording to the exemplary embodiment;

FIG. 5 illustrates a data structure of a color chart table according tothe exemplary embodiment;

FIG. 6 illustrates a data structure of a user table according to theexemplary embodiment;

FIG. 7 illustrates a data structure of a target object table accordingto the exemplary embodiment;

FIG. 8 illustrates a data structure of an estimated target object colortable according to the exemplary embodiment;

FIGS. 9A and 9B illustrate a flow of the color identification methodaccording to the exemplary embodiment;

FIG. 10 illustrates a state in which the color chart is attached to atarget object in accordance with the color identification methodaccording to the exemplary embodiment;

FIG. 11 illustrates a report screen displayed on a terminal apparatusaccording to the exemplary embodiment;

FIG. 12 illustrates a report screen displayed on the terminal apparatusaccording to the exemplary embodiment; and

FIG. 13 illustrates a state in which the color chart is attached to atarget object in accordance with a color identification method accordingto a modification.

DETAILED DESCRIPTION

A color identification method M according to an exemplary embodiment ofthe present invention will be described below. The color identificationmethod M is a method for estimating a color of a target object obtainedif the color of the target object were measured with a color measuringdevice, instead of measuring the color of the target object with thecolor measuring device.

FIG. 1 illustrates apparatuses and the like used in the coloridentification method M. A color chart 1, a color measuring device 2, animage capturing apparatus 3, a terminal apparatus 4, and a dataprocessing apparatus 5 are used in the color identification method M. Atarget object 9 illustrated in FIG. 1 is a target object whose color isto be estimated. The target object 9 illustrated in FIG. 1 is part of abrick wall.

The color chart 1 is a sheet-like medium. The color chart 1 is attachedto the target object 9, and in that state an image of the color chart 1and the target object 9 is captured with the image capturing apparatus3. The color measuring device 2 is a device that measures color sampleson the color chart 1. The color measuring device 2 measures a color of atarget object without being affected by the intensity and the frequencycharacteristics of light, for example. The image capturing apparatus 3captures an image of the target object 9 having the color chart 1attached thereto. The terminal apparatus 4 transmits image datarepresenting the image captured with the image capturing apparatus 3 tothe data processing apparatus 5. The data processing apparatus 5estimates a measured value obtained if the color of the target object 9were measured with the color measuring device 2, on the basis of themeasured values of the color samples on the color chart 1 which areobtained by the color measuring device 2 and the image captured with theimage capturing apparatus 3.

FIG. 1 illustrates one color chart 1, one image capturing apparatus 3,one terminal apparatus 4, and one target object 9. However, in practice,for each of the plural target objects 9, the color chart 1 that isattached to the target object 9 and is subjected to image capturing, theimage capturing apparatus 3 that captures an image of the target object9, and the terminal apparatus 4 that transmits image data representingthe image of the target object 9 to the data processing apparatus 5 areused.

FIG. 2 illustrates the color chart 1. The color chart 1 is a sheet-likemedium (e.g., paper or plastic sheet) having multiple color samplesthereon. In the color chart 1 illustrated in FIG. 2, color samples arevertically arranged in seven rows on the white background. Fourdifferent color samples are arranged in odd-numbered rows among theseven rows, and three different color samples are arranged ineven-numbered rows. Note that two color samples and one hole arearranged in the fourth row instead of three color samples, as describedlater. The color samples are painted in squares of the same size, andhorizontally adjacent color samples are spaced apart by half the lengthof the side of the squares of the color samples. In addition, the colorsamples in the odd-numbered rows and the color samples in theeven-numbered rows are horizontally shifted from each other by half thelength of the side of the squares of the color samples.

Evenly spaced black dots are vertically arranged on the left and rightsides of an area where the color samples are arranged. In addition, ahorizontally extending black rectangular bar is arranged on the upperside of the area where the color samples are arranged. These dots andbar are markers used by the data processing apparatus 5 to identify anarea of each color sample in the image captured with the image capturingapparatus 3.

A two-dimensional image code is arranged on the lower side of the areawhere the color samples are arranged. The two-dimensional image code isan identifier for identifying the color chart 1 from the other colorcharts 1. In this exemplary embodiment, color uniformity is guaranteedfor the plural color charts 1 of the same production lot even if thecolor charts 1 are used for the different target objects 9. Accordingly,the color charts 1 of the same production lot are treated as those neednot be distinguished from one another. That is, the same two-dimensionalimage code is arranged on the plural color charts 1 of the sameproduction lot.

An image-capturing window 11, which is a square through-hole having asize that is the same as the size of the squares of the color samples,is provided at the center in the horizontal direction in the fourth rowamong the seven rows in which the color samples are arranged. Theimage-capturing window 11 is a hole provided to allow the imagecapturing apparatus 3 to capture an image of the target object 9 withthe color chart 1 being attached the target object 9. That is, the imagecapturing apparatus 3 is able to capture an image of the target object 9located behind the color chart 1 through the image-capturing window 11.

Since the color measuring device 2 is a commonly-used known colormeasuring device, a description thereof is omitted. Since the imagecapturing apparatus 3 is a commonly-used known digital camera having afunction of determining the location thereof using a satellitepositioning system or the like, a description thereof is omitted. Sincethe terminal apparatus 4 is a commonly-used known terminal apparatushaving a browser function for displaying a website provided by the dataprocessing apparatus 5, a description thereof is omitted. Note that, forexample, a tablet computer including a digital camera may be used as anapparatus serving as both the image capturing apparatus 3 and theterminal apparatus 4.

In this exemplary embodiment, the data processing apparatus 5 isimplemented by a computer. Specifically, the computer performs dataprocessing based on a program according to this exemplary embodiment,thereby functioning as the data processing apparatus 5. FIG. 3illustrates a configuration of a computer 10 used to implement the dataprocessing apparatus 5. The computer 10 includes a memory 101, aprocessor 102, a communication interface (I/F) 103, and an input/outputI/F 104. The memory 101 stores various kinds of data. The processor 102performs data processing in accordance with a program stored in thememory 101. The communication I/F 103 is an interface that performs datacommunication via a network with an external apparatus. The input/outputI/F 104 is an interface that receives and outputs operation data andimage data from and to an external apparatus. An operation device, suchas a keyboard or a mouse, and a display device, such as a liquid crystaldisplay, are connected to the input/output I/F 104.

FIG. 4 illustrates a configuration of the data processing apparatus 5. Aprogram according to this exemplary embodiment causes the computer 10 tofunction as units illustrated in FIG. 4. The data processing apparatus 5includes an obtaining unit 51 and a storage unit 52. The obtaining unit51 obtains various kinds of data. The storage unit 52 stores variouskinds of data.

The data processing apparatus 5 also includes an identifying unit 53 anda converting unit 54. The identifying unit 53 identifies correspondenceseach between a measured value of a color obtained with the colormeasuring device 2 and a value of the color in an image captured withthe image capturing apparatus 3. The converting unit 54 converts, on thebasis of the correspondences identified by the identifying unit 53, avalue of a color of the target object 9 included in the image capturedwith the image capturing apparatus 3 into an estimated value of ameasured value of the color of the target object 9 obtained if the colorof the target object 9 were measured with the color measuring device 2.

The data processing apparatus 5 also includes a determining unit 55, anevaluating unit 56, and a transmitting unit 57. The determining unit 55determines whether image data received by the obtaining unit 51 from theterminal apparatus 4 satisfies a predetermined condition. The evaluatingunit 56 evaluates the color of the target object 9 on the basis of theestimated value of the color of the target object 9 obtained by theconverting unit 54 and a value of a reference color. The transmittingunit 57 transmits the determination result obtained by the determiningunit 55 and the evaluation result obtained by the evaluating unit 56 tothe terminal apparatus 4.

Roles of the individual units of the data processing apparatus 5 will bedescribed also in a description of the flow of the color identificationmethod M below.

Various kinds of data stored in the storage unit 52 will be describedbelow. FIG. 5 illustrates a data structure of a color chart table storedin the storage unit 52. The color chart table is a collection of recordseach for a corresponding one of the color charts 1. The color charttable includes fields “COLOR CHART ID” and “MEASURED COLOR SAMPLE”. Thefield “COLOR CHART ID” stores a color chart ID used to identify thecolor chart 1. The two-dimensional image code on the color chart 1 is animage obtained by encoding the color chart ID stored in the field “COLORCHART ID”.

The field “MEASURED COLOR SAMPLE” stores measured color sample datarepresenting values obtained by measuring respective color samples onthe color chart 1 with the color measuring device 2. In this exemplaryembodiment, the values obtained by measuring the respective colors withthe color measuring device 2 are values according to CIE Lab (L*a*b*color space).

FIG. 6 illustrates a data structure of a user table stored in thestorage unit 52. The user table is a collection of records each for acorresponding one of users of a color identification service provided bythe data processing apparatus 5. The user table includes fields “USERID” and “PASSWORD”. The field “USER ID” stores data representing thename of a user. The field “PASSWORD” stores a password used forauthentication of the user.

FIG. 7 illustrates a data structure of a target object table stored inthe storage unit 52. The target object table is a collection of recordseach for a corresponding one of the plural target objects 9. The targetobject table includes fields “TARGET OBJECT NAME”, “LOCATION”, and “USERID”. The field “TARGET OBJECT NAME” stores data representing the name ofthe target object 9. The field “LOCATION” stores location datarepresenting the location of the target object 9 using the longitude andlatitude. In this exemplary embodiment, the target objects 9 aredistinguished from one another based on the location data. The field“USER ID” stores the user ID of the user who is a person requestingidentification of the color of the target object 9.

FIG. 8 illustrates a data structure of an estimated target object colortable stored in the storage unit 52. The estimated target object colortable is stored in the storage unit 52 in association with each targetobject 9 and stores estimated target object color data representing theestimated value of the color of the target object 9 obtained by theconverting unit 54. The estimated target object color table is acollection of records each for a corresponding one of images used toestimate the value of the color of the target object 9. The estimatedtarget object color table includes fields “IMAGE-CAPTURING DATE/TIME”and “ESTIMATED TARGET OBJECT COLOR”.

The field “IMAGE-CAPTURING DATE/TIME” stores data representing the dateand time at which the image used to estimate the value of the color ofthe target object 9 has been captured. The field “ESTIMATED TARGETOBJECT COLOR” stores estimated target object color data representing avalue (value according to the L*a*b* color space) of the color of thetarget object 9 estimated by the converting unit 54 on the basis of theimage.

The flow of the color identification method M will now be described.FIGS. 9A and 9B illustrate the flow of the color identification methodM. An administrator of the data processing apparatus 5 (hereinafter,simply referred to as an administrator) measures each of the colorsamples on the color chart 1 using the color measuring device 2 (stepS101). The administrator then inputs the color chart ID of the colorchart 1 on which the measurement has been performed using the colormeasuring device 2 and the measured values (values according to theL*a*b* color space) of the color samples obtained by the color measuringdevice 2 to the data processing apparatus 5, for example, using akeyboard connected to the data processing apparatus 5 (step S102). Theadministrator performs operations of steps S101 and S102 for eachproduction lot of the color charts 1.

In response to the input operation performed by the administrator instep S102, the data processing apparatus 5 adds a new record to thecolor chart table (FIG. 5), and stores the color chart ID input by theadministrator at the field “COLOR CHART ID” of the added record andstores the measured color sample data representing the measured valuesof the color samples input by the administrator at the field “MEASUREDCOLOR SAMPLE” of the added record (step S103).

The administrator then puts the color chart 1 in an envelope having agood light-shielding property and sends it to a user who is, forexample, an owner of the target object 9 whose color is to be identified(step S104). The user receives the color chart 1 sent from theadministrator (step S105) and stores the color chart 1 in the envelopehaving a good light-shielding property except when it is used.

When the user wishes to identify the color of the target object 9, theuser temporarily attaches the color chart 1 to the target object 9 (stepS106). For example, if the target object 9 is part of a large object asillustrated in FIG. 1 and the user wishes to identify the color of thetarget object 9 multiple times, the user records the position where thecolor chart 1 is initially attached, for subsequent color identificationprocesses.

FIG. 10 illustrates a state in which the color chart 1 is attached tothe target object 9 that is part of a brick wall, for example. Adjacentbricks in the brick wall illustrated in FIG. 10 have different colors.Accordingly, if the position where the color chart 1 is attached to thewall during the first color identification process differs from theposition of the color chart 1 during the second color identificationprocess, a target for which the color is identified changes.Accordingly, for example, the user may mark the attached position of thecolor chart 1 to allow the color chart 1 to be attached to the sameposition of the wall during the second and later color identificationprocesses.

After the color chart 1 has been attached to the target object 9 (stepS106 in FIG. 9A), the user captures an image of the color chart 1attached to the target object 9 from the front using the image capturingapparatus 3 (step S107). The image captured with the image capturingapparatus 3 includes the color chart 1 and the target object 9 seenthrough the image-capturing window 11 of the color chart 1. Image datarepresenting the image captured with the image capturing apparatus 3 hasdate/time data and location data added thereto. The date/time dataindicates the date/time at which the image has been captured with theimage capturing apparatus 3. The location data indicates the location ofthe image capturing apparatus 3 at the time of image capturing by usingthe latitude and longitude.

After finishing capturing the image, the user takes off the color chart1 from the target object 9 and puts the color chart 1 in the envelopehaving a good light-shielding property. The user then causes theterminal apparatus 4 to load the image data generated by the imagecapturing apparatus 3 via, for example, a recording medium, and thencauses the browser of the terminal apparatus 4 to display a login screenof a website provided by the data processing apparatus 5, inputs theuser ID and the password, and logs in to the website (step S108). Thedata processing apparatus 5 checks that the user ID and the passwordtransmitted from the terminal apparatus 4 in step S108 match data storedin any of the records of the user table (FIG. 6). In this way, the dataprocessing apparatus 5 successfully identifies the user (step S109). Ifthe user ID and the password do not match the data and the login attemptis unsuccessful, the data processing apparatus 5 transmits, to theterminal apparatus 4, an error message requesting re-input of a password(FIG. 9A omits illustration).

Then, the user causes the browser of the terminal apparatus 4 to displayan image data uploading screen and performs an operation for uploadingthe image data representing the image captured in step S107 to the dataprocessing apparatus 5. In response to the operation, the image data istransmitted from the terminal apparatus 4 to the data processingapparatus 5 (step S110).

The obtaining unit 51 of the data processing apparatus 5 receives theimage data transmitted from the terminal apparatus 4 (step S111). Theimage data received by the obtaining unit 51 is temporarily stored inthe storage unit 52. The determining unit 55 then determines whether thereceived image data satisfies a predetermined condition (step S112). Thepredetermined condition used in the determination in step S112 may be acondition as to whether or not a brightness, a color irregularity, adistortion, an out-of-focus degree, a reflection, a runout, a size, orthe like of the image represented by the image data is within apredetermined range.

If it is determined in step S112 that the image data does not satisfythe predetermined condition (NO in step S112), the transmitting unit 57transmits, to the terminal apparatus 4, an error message requestingre-transmission of image data (step S113). Upon receipt of the errormessage transmitted from the data processing apparatus 5 in step S113(step S114), the terminal apparatus 4 displays the error message (stepS115). In response to the error message displayed in step S115, the userperforms operations of steps S106 to S108 and S110 again aftertemporarily logging out from the website, for example.

If it is determined in step S112 that the image data received by thedata processing apparatus 5 from the terminal apparatus 4 satisfies thepredetermined condition (YES in step S112), the obtaining unit 51 readsfrom the target object table (FIG. 7) the target object namecorresponding to location data added to the image data. In this way, thedata processing apparatus 5 successfully identifies the target object 9for which color identification is performed (step S116).

The obtaining unit 51 then decodes the two-dimensional image codeincluded in the image represented by the image data into the color chartID. In this way, the data processing apparatus 5 successfully identifiesthe color chart 1 used for capturing of the image (step S117). Theobtaining unit 51 then reads and obtains from the color chart table(FIG. 5) the measured color sample data corresponding to the color chartID indicated by the two-dimensional image code (step S118).

The identifying unit 53 then identifies values of the multiple colorsamples included in the image data and a value of a color of the targetobject 9 included in the image data (step S119). In step S119, theidentifying unit 53 performs corrections such as brightness correctionand distortion connection on the image data if necessary and thenidentifies areas of the color samples and an area of the image-capturingwindow 11 (the target object 9) in the image with reference to themarkers (the dots and the bar) on the color chart 1 included in theimage. For each of the identified areas, the identifying unit 53specifies a representative value (e.g., an average value) of colorvalues of pixels included in the area as the value of the correspondingcolor sample or the value of the color of the target object 9 in theimage. The identifying unit 53 temporarily stores data representing thevalues of the color samples in the image as the captured color sampledata in the storage unit 52. In addition, the identifying unit 53temporarily stores data representing the value of the color of thetarget object 9 in the image as the captured target object color data inthe storage unit 52.

In this exemplary embodiment, the image captured with the imagecapturing apparatus 3 is a collection of pixels each represented by avalue according to the RGB color model. Accordingly, the captured colorsample data and the captured target object color data generated by theidentifying unit 53 in step S119 represent colors by using valuesaccording to the RGB color model.

The identifying unit 53 then identifies correspondences each between avalue of a color measured by the color measuring device 2 and a value ofthe color in the image represented by the image data transmitted fromthe terminal apparatus 4, on the basis of the measured values of thecolor samples obtained by the color measuring device 2 (values accordingto the L*a*b* color space) represented by the measured color sample dataobtained as a result of the obtaining unit 51 reading the measured colorsample data from the color chart table in step S118 and the values ofthe color samples (values according to the RGB color model) in the imagerepresented by the captured color sample data temporarily stored in stepS119 (step S120).

In this exemplary embodiment, the identifying unit 53 identifies atransform matrix H using the multiple regression analysis, as thecorrespondences between the measured values of the colors obtained bythe color measuring device 2 and the values of the respective colors inthe image. The transform matrix H is a matrix that makes the individualvalues of the multiple color samples represented by the captured colorsample data match the values of the respective color samples representedby the measured color sample data as much as possible. That is, theidentifying unit 53 identifies the transform matrix H that minimizes adifference between a vector having the measured values of the colorsamples represented by the measured color sample data as its elementsand a vector obtained by multiplying a vector having the values of themultiple color samples represented by the captured color sample data asits elements by the transform matrix H.

Then, the converting unit 54 reads, from the storage unit 52, thecaptured target object color data temporarily stored in step S119 andconverts, on the basis of the transform matrix H identified by theidentifying unit 53 in step S120, the read captured target object colordata into estimated target object color data representing an estimatedvalue of the color of the target object 9 identified if the color of thetarget object 9 were measured with the color measuring device 2 (stepS121). Specifically, the converting unit 54 generates, as the estimatedtarget object color data, data representing a value obtained bymultiplying the value represented by the captured target object colordata by the transform matrix H. Note that the value represented by theestimated target object color data is a value according to the L*a*b*color space.

The converting unit 54 then adds a new record to the estimated targetobject color table (FIG. 8) corresponding to the target object name ofthe target object 9 identified in step S116 and stores, in the addedrecord, the date/time data added to the image data received by the dataprocessing apparatus 5 from the terminal apparatus 4 in step S111 andthe estimated target object color data generated by the conversion instep S121 (step S122).

Then, the evaluating unit 56 determines whether the estimated targetobject color table to which the new record has been added in step S122has plural records (step S123). When the estimated target object colordata is generated for the first time in step S121 for the certain targetobject 9, the estimated target object color table for the target object9 includes only one record. Thus, the evaluating unit 56 determines instep S123 that the estimated target object color table corresponding tothe target object 9 does not have plural records (NO in step S123). Insuch a case, the evaluating unit 56 generates data of a report screenfor notifying the user of the identified value of the color of thetarget object 9, without evaluating the color of the target object 9 onthe basis of the color of the target object 9 identified in the past andthe color of the target object 9 identified this time (step S125).

The transmitting unit 57 transmits the data of the report screengenerated by the evaluating unit 56 to the terminal apparatus 4 (stepS126). The terminal apparatus 4 receives, as a response to the imagedata transmitted in step S110, the data of the report screen transmittedfrom the data processing apparatus 5 in step S126 (step S127). Theterminal apparatus 4 displays the report screen using the browser inaccordance with the received data (step S128).

FIG. 11 illustrates a report screen displayed on the terminal apparatus4 when the color of the certain target object 9 is identified for thefirst time. This report screen shows the value represented by theestimated target object color data generated in step S121, that is, theestimated value identified if the color of the target object 9 weremeasured with the color measuring device 2, together with the name ofthe target object 9 and the image-capturing date/time.

The user is able to know objective values indicating the change in thecolor of the target object 9 by repeatedly performing identification ofthe color of the target object 9 using the data processing apparatus 5,for example, at intervals of a predetermined period after performing theabove-described identification of the color of the target object 9 usingthe data processing apparatus 5 once.

If the user repeatedly performs the operations of step S106 to S108 andS110 at certain intervals, the evaluating unit 56 determines in stepS123 for the second and following times that the estimated target objectcolor table (FIG. 8) corresponding to the target object 9 has pluralrecords (YES in step S123). In such a case, the evaluating unit 56evaluates the color of the target object 9 on the basis of the estimatedtarget object color data generated by the converting unit 54 in theprocessing of step S121 performed for the first time and the estimatedtarget object color data generated by the converting unit 54 in stepS121 performed this time (step S124).

In this exemplary embodiment, the evaluating unit 56 uses the estimatedtarget object color data generated for the first time by the convertingunit 54 as reference color data representing a value of a referencecolor of the target object 9. The evaluating unit 56 then identifies acolor difference (ΔE), a chroma difference (ΔC), and a hue difference(Δh) of the color represented by the estimated target object color datagenerated by the converting unit 54 this time from the color representedby the reference color data, as an evaluation result of the color of thetarget object 9 at that time.

The evaluating unit 56 then generates data of a report screen that showsthe evaluation result obtained in step S124 (step S125). The data of thereport screen thus generated is transmitted from the data processingapparatus 5 to the terminal apparatus 4 (step S126) and is received bythe terminal apparatus 4 (step S127). The terminal apparatus 4 displaysthe report screen using the browser in accordance with the data receivedfrom the data processing apparatus 5 (step S128).

FIG. 12 illustrates a report screen displayed on the terminal apparatus4 when identification of the color of the certain target object 9 isperformed multiple times. This report screen shows a color difference(ΔE), a chroma difference (ΔC), and a hue difference (Δh) of the colorof the target object 9 identified this time from the color of the targetobject 9 identified for the first time together with the name of thetarget object 9, the image-capturing date/time, and the value of thecolor of the target object 9 identified this time. In addition, how thecolor-difference has changed is displayed in a graph.

The user is able to know the estimated value of the color of the targetobject 9 obtained if the color of the target object 9 were measured withthe color measuring device 2 on the report screen displayed on theterminal apparatus 4, without measuring the color of the target object 9with the color measuring device 2.

For example, if the target object 9 is a wall of a store, the color ofthe target object 9 gradually fades over time because of the influenceof sunlight or the like. However, it is not easy to correctly evaluatethe change in the color of the target object 9 with the human eyebecause the change in the color is gradual and the color looksdifferently each time to the human eye depending on a factor, such asthe weather or the time period. Accordingly, it is difficult todetermine when to repaint the wall of the store with the human eye.

If the color of the target object 9 is directly measured with the colormeasuring device 2, the change in the color of the target object 9 isrepresented by a numeric value, and it becomes possible to reasonablydetermine a timing to repaint the wall, for example. However, the colormeasuring device 2 is relatively expensive despite its frequency of use.In contrast, the color identification method M according to theexemplary embodiment allows the user to obtain, generally at a lowercost, information that is substantially the same as the informationobtained if the color of the target object 9 were measured with thecolor measuring device 2, by transmitting, to the data processingapparatus 5, image data obtained by capturing an image of the targetobject 9 with a digital camera by using the color chart 1.

Modifications

The above-described exemplary embodiment is merely an example of how thepresent invention is embodied and may be variously modified. Examples ofsuch modifications will be described below. Note that two or more of theabove-described exemplary embodiment and plural modifications describedbelow may be combined as needed.

(1) The color chart 1 has one hole in the above-described exemplaryembodiment; however, the number of holes in the color chart 1 is notlimited to one. FIG. 13 illustrates a state in which the color chart 1having three holes is attached to a brick wall. In the exampleillustrated in FIG. 13, bricks seen through the three holes aredifferent bricks and have different colors.

When the color chart 1 illustrated in FIG. 13 is used, the target objectsubjected to color identification is each brick seen through acorresponding one of the three holes. That is, each of the three bricksis the target object 9 in this case, and the colors of these bricks areidentified.

If one image includes multiple target objects 9, values of the colors ofthe multiple target objects 9 in the image are converted, in accordancewith the same correspondence, into respective values of the colorsobtained if the colors were measured with the color measuring device 2.

In this modification, the determining unit 55 may determine whether thecolor identified, through conversion by the converting unit 54, for eachof the target objects 9 included in the image captured with the imagecapturing apparatus 3 at positions corresponding to the plural holes ofthe color chart 1 satisfies a predetermined condition.

For example, if the position where the color chart 1 is attached whenthe user has captured the first image matches the position where thecolor chart 1 is attached when the user has captured the second orfollowing image, the color differences (ΔE), the chroma differences(ΔC), and the hue differences (Δh) of the multiple target objects 9generally do not vary greatly because color fading of the target objects9 of the same kind progresses substantially in the same manner under thesame environment. However, if the position where the color chart 1 isattached for the first time differs from the position where the colorchart 1 is attached for the second or following time, the colordifferences (ΔE), the chroma differences (ΔC), and the hue differences(Δh) of the plural target objects 9 may vary greatly.

Accordingly, for example, the determining unit 55 may determine whetherthe color differences (ΔE) calculated for the plural target objects 9included in the captured image at the respective holes of the colorchart 1 are larger than or equal to a predetermined threshold. If thecolor differences (ΔE) are larger than the predetermined threshold, thetransmitting unit 57 may transmit to the terminal apparatus 4 an errormessage prompting the user to check the position where the color chart 1is attached. This consequently reduces an occurrence probability ofincorrect information regarding the color of the target object 9 beingprovided to the user because of the incorrect attachment position of thecolor chart 1.

In addition, when the color chart 1 has multiple holes, any of or all ofthe multiple holes may be used for position alignment when the colorchart 1 is attached to the target object 9.

(2) In the above-described exemplary embodiment, the measured values ofthe colors obtained with the color measuring device 2 are valuesaccording to the L*a*b* color space, whereas the values of the colors inthe image captured with the image capturing apparatus 3 are valuesaccording to the RGB color model. However, the measured values of thecolors obtained with the color measuring device 2 and the values of thecolors in the image captured with the image capturing apparatus 3 eachmay be values according to any color space. In addition, the measuredvalues of the colors obtained by the color measuring device 2 and thevalues of the colors in the image captured with the image capturingapparatus 3 may be values according to the same color space.

(3) In the above-described exemplary embodiment, the identifying unit 53identifies, using the multiple regression analysis, a transform matrixrepresenting correspondences between the measured values of the colorsobtained with the color measuring device 2 and the values of the colorsin the image captured with the image capturing apparatus 3. The methodused by the identifying unit 53 to identify the correspondences is notlimited to the multiple regression analysis, and the format representingthe identified correspondences is not limited to a matrix. For example,the identifying unit 53 may identify, using a neural network,correspondences between the measured values of the colors obtained withthe color measuring device 2 and the values of the colors in the imagecaptured with the image capturing apparatus 3. In addition, theidentifying unit 53 may generate data representing the correspondencesusing a lookup table (LUT) format.

(4) In the above-described exemplary embodiment, the evaluating unit 56uses the estimated target object color data generated for the first timeas the reference color data when calculating the color difference (ΔE)and the like; however, the reference color data is not limited to theestimated target object color data generated for the first time. Forexample, reference color data representing a value of a standard colorset in advance for the target object 9 may be used.

(5) In the above-described exemplary embodiment, the color chart 1 has ahole; however, the color chart 1 need not necessarily have a hole. Forexample, the color chart 1 may have a cut portion at any of the cornersinstead of the hole, and the value of the color of the target object 9at the cut portion in the captured image may be identified. In addition,the color chart 1 may include neither a hole not a cut portion, thecolor chart 1 may be attached to the target object 9, and an image maybe captured so that the color chart 1 and the target object 9 arearranged side by side. That is, both the color chart 1 and the targetobject 9 are just required to be in an image captured with the imagecapturing apparatus 3.

(6) In the above-described exemplary embodiment, an image is capturedwith the image capturing apparatus 3 in a state in which the color chart1 is attached to the target object 9; however, the color chart 1 neednot be attached to the target object 9. For example, an image of thecolor chart 1 and the target object 9 may be captured in a state inwhich the user is holding the color chart 1 so that the color chart 1 islocated on the image capturing apparatus 3 side of the target object 9.

(7) In the above description of the exemplary embodiment, a brick wallis used as an example of the target object 9; however, the kind of thetarget object 9 is not limited. In addition, the usage of the value ofthe color of the target object 9 identified using the coloridentification method M is not limited. For example, the value of thecolor of a bolt may be identified using the color identification methodM, and the identified value of the color of the bolt may be used todetermine the corrosion degree of the bolt.

(8) Some or all of the operations performed by the administrator or theuser in the above description of the exemplary embodiment may beperformed by an apparatus instead of a person. For example, in theabove-described exemplary embodiment, the administrator measures thecolor samples on the color chart 1 using the color measuring device 2and inputs the measurement results to the data processing apparatus 5.These operations may be performed by an apparatus that measures thecolor samples on the color chart 1 once the color chart 1 is placedthere, generates the measured color sample data representing theresults, and transmits the measured color sample data to the dataprocessing apparatus 5. In addition, an operation for capturing an imageof the color chart 1 and the target object 9 may be performed by arobot.

(9) In the above-described exemplary embodiment, the data processingapparatus 5 identifies the target object 9 using the location data addedto the image data; however, another kind of data, such as the targetobject ID assigned to each of the target objects 9, may be used as datafor identifying the target object 9.

(10) In the above-described exemplary embodiment, the value of the colorof the target object 9 in the image alone is converted by the convertingunit 54. Instead of this configuration, the entire image may besubjected to conversion by the converting unit 54. In this case, thevalue of the color of the target object 9 in the converted image is theestimated value of the color of the target object 9 obtained if thecolor of the target object 9 were measured with the color measuringdevice 2.

(11) In the above-described exemplary embodiment, the color chart 1 is asheet-like medium; however, the color chart 1 is not limited to thesheet-like medium. In addition, the design of the color chart 1 is notlimited to the design described in the exemplary embodiment above.

(12) In the above-described exemplary embodiment, the color chart 1 isidentified on a production lot basis. Instead of this configuration, thecolor chart is may be identified from one another. In addition, thecolor charts 1 of different production lots having the same colorsamples may be not distinguished from one another, and color charts 1having different color samples may be distinguished from one another.

(13) In the above-described exemplary embodiment, the data processingapparatus 5 is implemented as a result of the general-purpose computer10 performing data processing based on a program. Instead of thisconfiguration, the data processing apparatus 5 may be configured by adedicated apparatus.

(14) The program causing the computer 10 to function as the componentsof the data processing apparatus 5 in the above-described exemplaryembodiment may be downloaded to the computer 10 via a communication linesuch as the Internet. In addition, this program may be distributed afterbeing stored in a recording medium that non-volatilely stores data andmay be read by the computer from the recording medium.

The foregoing description of the exemplary embodiment of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiment was chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

What is claimed is:
 1. A data processing apparatus comprising: acomputer programmed to execute a process of: obtaining measured colorsample data and image data, the measured color sample data representingvalues obtained by measuring a plurality of color samples on a colorchart with a color measuring device, the image data representing animage of the color chart and a target object captured with an imagecapturing apparatus; converting captured target object color data intoestimated target object color data, based on: (i) the measured colorsample data, which is the measured color sample data representing valuesobtained by measuring the plurality of color samples on the color chartwith the color measuring device; and (ii) captured color sample datarepresenting values of the plurality of color samples included in theimage data, the captured target object color data representing a valueof a color of the target object included in the image data, theestimated target object color data representing an estimated value ofthe color of the target object identified if the color of the targetobject were measured with the color measuring device; obtainingreference color data representing a value of a reference color of thetarget object; generating evaluation data representing a result obtainedby evaluating the color of the target object based on the estimatedtarget object color data and the reference color data; and displaying areport based on the evaluation data.
 2. The data processing apparatusaccording to claim 1, wherein the computer is further programmed toexecute a process of obtaining the estimated target object color datagenerated using the image data representing an image captured at a firsttime point, as the reference color data used in evaluation performedbased on the estimated target object color data generated using theimage data representing an image captured at a second time point.
 3. Thedata processing apparatus according to claim 1, wherein the computer isfurther programmed to execute a process of obtaining location datarepresenting a location where the image represented by the image datahas been captured, identifying the target object from other targetobjects based on the location data, and obtaining the reference colordata corresponding to the identified target object.
 4. The dataprocessing apparatus according to claim 1, wherein the color chart hasan identifier for identifying the color chart from other color charts,and wherein the computer is further programmed to execute a process ofidentifying the color chart based on the identifier of the color chartincluded in the image represented by the image data and obtaining themeasured color sample data corresponding to the identified color chart.5. The data processing apparatus according to claim 1, wherein the colorchart has a plurality of holes, and wherein the computer is furtherprogrammed to execute a process of determining whether values of colorsof the target object at positions of the plurality of holes in the imagerepresented by the image data each satisfy a predetermined condition. 6.A color identification method comprising: measuring, with a colormeasuring device, a plurality of color samples on a color chart;capturing, with an image capturing apparatus, an image of the colorchart and a target object; converting, based on: (i) measured values ofthe plurality of color samples obtained in the measuring, the measuredvalues representing values obtained by measuring the plurality of colorsamples on the color chart with the color measuring device; and (ii)values of the plurality of color samples included in image datarepresenting the image captured in the capturing, a value of a color ofthe target object included in the image data into an estimated value ofthe color of the target object identified if the color of the targetobject were measured with the color measuring device; obtainingreference color data representing a value of a reference color of thetarget object; generating evaluation data representing a result obtainedby evaluating the color of the target object based on the estimatedvalue of the color of the target object and the reference color data;and displaying a report based on the evaluation data.
 7. Anon-transitory computer readable medium storing a program causing acomputer to execute a process, the process comprising: obtainingmeasured color sample data and image data, the measured color sampledata representing values obtained by measuring a plurality of colorsamples on a color chart with a color measuring device, the image datarepresenting an image of the color chart and a target object capturedwith an image capturing apparatus; and converting captured target objectcolor data into estimated target object color data, based on: (i) themeasured color sample data, which is the measured color sample datarepresenting values obtained by measuring the plurality of color sampleson the color chart with the color measuring device; and (ii) capturedcolor sample data representing values of the plurality of color samplesincluded in the image data, the captured target object color datarepresenting a value of a color of the target object included in theimage data, the estimated target object color data representing anestimated value of the color of the target object identified if thecolor of the target object were measured with the color measuringdevice; obtaining reference color data representing a value of areference color of the target object; generating evaluation datarepresenting a result obtained by evaluating the color of the targetobject based on the estimated target object color data and the referencecolor data; and displaying a report based on the evaluation data.
 8. Acolor chart comprising: a plurality of color samples on the color chart,wherein the plurality of color samples are squares of the same size, thecolor chart is a sheet-like medium having one or more through-holes, andeach through-hole is a square through-hole having a size that is thesame as the size of the squares of the color samples.
 9. The color chartaccording to claim 8, further comprising: an identifier for identifyingthe color chart from other color charts thereon.
 10. The data processingapparatus according to claim 1, wherein the computer is furtherprogrammed to execute the process of displaying the report inassociation with the value represented by the evaluation data when theestimated target object color data of the target object is generatedmultiple times.
 11. The data processing apparatus according to claim 1,wherein the report includes a representation of the estimated targetobject color data of the target object at multiple different dates.